JPH102324A - Fluid bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exhibit the substantially same bearing performance even if a rotating shaft is rotated in either direction by forming a first fluid film in a space between the shaft and a bearing member when the rotating shaft is rotated in a first direction, and forming a second fluid film in the space between the shaft and the bearing when it is rotated in a second direction opposite to the first direction. SOLUTION: A first spiral groove part 12 between a shaft 10 and a bearing member 32 for supporting it, and a second spiral groove part 14 in an upper adjacent position are formed in the central part in the longitudinal direction of the shaft 10. A lower position adjacent to the groove part 12, a third spiral groove part 16 is formed. The spiral directions of the groove parts 14 and 16 are opposite to the direction of the groove part 12, and the positions of the groove parts 14 and 16 are substantially symmetrical about the groove part 12. If the shaft 10 is rotated clockwise, a lubricating fluid supplied by the groove parts 12, 14 forms a first fluid film in a position R1, and if it is rotated counterclockwise, the lubricating fluid forms a second fluid film in the position R2 by the groove parts 12, 16. The respective groove parts are reverse spiral, it can cope with reverse rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid bearing used for an axial fan motor, a spindle motor and the like.

[0002]

2. Description of the Related Art As a conventional fluid bearing, for example, as disclosed in Japanese Patent Application Laid-Open No. 58-109715, two radial bearings are provided at required positions after restricting the rotation direction to one direction. Are known.

[0003]

However, this conventional bearing has the following problems. (1) Since the spiral groove for forming the fluid film is arranged at a position near the center of the shaft and a position near one end of the shaft, the direction of insertion into the bearing member supporting the shaft is one direction. Is limited to (2) Although the bearing exerts a sufficient bearing function in one direction of rotation of the shaft, the function is almost lost in the opposite direction of rotation.

[0004] In particular, with regard to (1), when the shaft and the rotating body such as the rotor are joined by insert molding, the direction of the shaft for fixing the rotating body is limited to one direction. If the shaft is mounted on the rotating body in the opposite direction, it becomes unusable. Therefore, consideration must be given to mounting the shaft in the correct direction, and there is a problem that workability is extremely deteriorated.

Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to improve the workability of assembling and connecting a shaft and a rotating body, and to provide a fluid excellent in cost and quality. It is to provide a bearing.

[0006]

In order to solve the above-mentioned problems and achieve the object, a fluid bearing according to the present invention comprises a rotating shaft, a bearing member for rotatably supporting the rotating shaft, and a rotating shaft. First and second fluid film forming means provided in the vicinity of the central portion in the longitudinal direction, wherein a fluid film is formed between the rotating shaft and the bearing member when the rotating shaft rotates in the first direction. Second fluid film forming means for forming a fluid film between the first fluid film forming means and the bearing member when the rotating body rotates in a second direction opposite to the first direction. Are provided.

Further, in the fluid bearing according to the present invention, the first fluid film forming means includes a first spiral groove formed at a substantially central portion in a longitudinal direction of the rotating shaft; A second groove formed spirally in a direction opposite to the direction of the first groove at a position formed on one side of the groove, and the second fluid film forming means includes the first fluid film forming means. And a third groove formed in a spiral shape opposite to the direction of the first groove formed on the other side of the first groove. I have.

In the fluid bearing according to the present invention, the second groove and the third groove are formed substantially symmetrically with respect to the first groove.

Further, in the fluid bearing according to the present invention, the end of the rotary shaft is formed in a substantially spherical shape, and the end is brought into contact with a support surface to regulate the position in the thrust direction. Features.

Further, in the fluid bearing according to the present invention, both ends of the shaft are substantially symmetrical with respect to a center portion of the shaft, a rotating body is attached to one end of the shaft, and the other end is formed in a thrust direction. It is characterized in that it is used for position regulation.

In the fluid bearing according to the present invention, when the shaft rotates in the first direction, a fluid film is formed by the first groove and the second groove, and the third groove is formed. Is characterized in that it serves to supply fluid to the end of the shaft.

Further, in the fluid bearing according to the present invention, when the shaft rotates in the second direction, a fluid film is formed by the first groove portion and the third groove portion, and the second groove portion is formed. Is characterized in that it serves to supply fluid to the end of the shaft.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a view showing the structure of a shaft 10 used in a hydrodynamic bearing according to one embodiment.

In FIG. 1, a fluid is provided between the shaft 10 and a bearing member 32 (see FIG. 2) supporting the shaft at a longitudinal center portion (position L / 2 from the end) of the shaft 10 having a total length L. A spiral first groove 12 for forming a film is formed. A helical second groove 14 is formed at an adjacent position above the first groove 12 in the drawing, and a helical second groove 14 is formed at a position adjacent to the first groove 12 below the drawing. The third
Groove 16 is formed. The directions of the spirals of the second and third grooves are set to be opposite to the directions of the spirals of the first groove 12, and the positions of the second groove 14 and the third groove 16 are the first groove. 12 are set at positions substantially symmetrical with respect to the center. Further, both end portions 18 and 20 of the shaft 10 are formed in a substantially spherical shape, and by receiving these end surfaces on the support surface 37 (see FIG. 2), the shaft 10 also functions as a thrust bearing. Grooves 22 and 24 are formed slightly inside both ends of the shaft 10 so as to improve the coupling property when a rotating body such as a rotor is insert-molded on the shaft 10.

The operation of the bearing using the shaft 10 configured as described above will be described below.

First, when the shaft 10 rotates clockwise as viewed from the direction of the arrow P, the shaft 10 is supplied between the shaft 10 and the bearing member 32 by the action of the first groove 12 and the second groove 14. The lubricating fluid collected at the position R1 forms a fluid film at this position. This fluid film floats the shaft 10 from the bearing member 32 and acts as a bearing. When the shaft 10 rotates counterclockwise when viewed from the direction of arrow P, the lubrication supplied between the shaft 10 and the bearing member 32 by the action of the first groove portion 12 and the third groove portion 16. The fluid is collected at the location R2, forming a fluid film at this location. This fluid film also floats the shaft 10 from the bearing member 32 and acts as a bearing. At this time, from the ends 18 and 20 of the shaft 10, R
Although the distances to 1 and R2 are not exactly the same, they are substantially equal distances, and substantially the same bearing performance can be obtained when the shaft 10 rotates in either the clockwise direction or the counterclockwise direction. Therefore, by adopting the above structure, a bearing corresponding to a rotating machine that rotates in both directions is provided. This is the first effect of the present embodiment.

Next, the effect when the rotation direction of the shaft 10 is limited to one direction will be described.

First, a case will be considered in which a rotating body is attached to the end portion 18 of the shaft 10 and the end portion 20 is received by the support surface 37 to operate as a radial and thrust bearing. At this time, if the shaft 10 is rotated clockwise as viewed from the direction of the arrow P, the fluid supplied between the shaft 10 and the bearing member 32 is collected at the position R1, and the fluid in the radial direction is moved to this position. A fluid bearing is formed. The lubricating fluid is also supplied to the end 20 of the shaft 10 by the action of the third groove 16,
The lubricating fluid also spreads to the contact portion between the end portion 20 and the support surface 37 in the thrust direction, so that lubrication in both the radial direction and the thrust direction can be performed.

When the shaft 10 is turned upside down and a rotating body is mounted on the end 20 of the shaft 10 and the end 18 is received from below by the support surface 37, the shaft 10 is viewed from above. When rotated in the clockwise direction, the same operation as described above can be obtained. That is, a radial fluid bearing is formed at the position R2 by the action of the first and third grooves 12, 16, and the end 18 and the support surface 3 are formed by the action of the second groove 14.
The fluid is supplied to the contact point 7. Therefore, it is possible to perform lubrication in both the radial direction and the thrust direction.

As described above, if the rotation direction of the shaft 10 is limited to one direction, lubrication in both the radial direction and the thrust direction can be performed regardless of whether the rotating body is mounted on the upper or lower side of the shaft 10. That is, when the rotating body is insert-molded on the shaft 10, the shaft 10 may be inserted in either direction, so that the production labor can be saved and the cost of the product can be reduced. This is the second effect of the present embodiment.

In the above description, the case where the shaft 10 is rotated in the clockwise direction has been described. However, if the direction of the spiral of the first to third grooves is completely reversed from that in FIG. Needless to say, it is possible to cope with the case of rotating in the direction.

FIG. 2 is a diagram showing an example in which the above-described fluid bearing is applied to an axial fan motor.

In FIG. 2, reference numeral 10 denotes a shaft for a fluid bearing described above, reference numeral 32 denotes a bearing member forming a fluid bearing in cooperation with the shaft 10, reference numeral 33 denotes a rotating body, and a fan to which a magnet 35 is fixed by bonding or the like. The rotating blades 34 are coils for generating a torque for applying a rotating force to the rotating blades 33, and are fixed to a housing 36 which is a stator. Also, the shaft 10
The rotating blades 33 are joined by insert molding, utilizing the characteristics of the plastic that is the material of the rotating blades 33. The lower end of the shaft 10 abuts on the support surface 37 and is supported in the thrust direction.

As described above, by using the shaft 10 shown in FIG. 1 for the axial fan motor shown in FIG. 2, a radial bearing can be formed regardless of the direction in which the shaft 10 is inserted into the rotating blades 33. The positions of the groove portions are the same with respect to the pivotal support position, and the functions of the individual groove portions are the same in the same rotational direction.

Therefore, since the direction of the insert is not limited, the forming process is easy and the processing error can be avoided. In addition, the groove near the lower end of the shaft that does not contribute to the radial bearing acts to guide the lubricating fluid to the contact point with the support surface 37, so that the frictional resistance of the support in the thrust direction can be reduced.

It should be noted that the present invention can be applied to a modification or modification of the above embodiment without departing from the gist thereof.

[0027]

As described above, according to the present invention, when the shaft rotates in both directions, there is provided a fluid bearing exhibiting substantially the same bearing performance regardless of the rotation in either direction.

Further, when the rotation direction of the shaft is limited to one direction, the insertion direction of the shaft with respect to the rotating body can be either direction, and the productivity can be improved.

[0029]

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a shaft used for a bearing according to an embodiment.

FIG. 2 is a diagram showing a configuration of an axial fan motor using the shaft shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 shaft 12 1st groove part 14 2nd groove part 16 3rd groove part 18,20 End part 22,24 groove 32 Bearing member 33 Rotating blade 34 Coil 35 Magnet 36 Housing 37 Support surface

Claims (7)

[Claims] 1. A rotating shaft, a bearing member rotatably supporting the rotating shaft, and first and second fluid film forming means provided near a central portion in a longitudinal direction of the rotating shaft, First fluid film forming means for forming a fluid film between the rotating shaft and the bearing member when the rotating shaft rotates in a first direction;
A fluid film forming means for forming a fluid film between itself and the bearing member when rotating in a second direction opposite to the direction of the fluid bearing. 2. The first fluid film forming means is formed at a spiral first groove formed substantially at a center in a longitudinal direction of the rotating shaft, and at one side of the first groove. A second groove formed in a helical shape opposite to the direction of the first groove at a location, wherein the second fluid film forming means includes the first groove and the first groove. The fluid according to claim 1, further comprising a spirally formed third groove formed in a direction opposite to the direction of the first groove formed on the other side of the groove. bearing. 3. The fluid bearing according to claim 2, wherein said second groove and said third groove are formed substantially symmetrically with respect to said first groove. 4. An end portion of the rotary shaft is formed in a substantially spherical shape, and the end portion is brought into contact with a support surface to regulate a position in a thrust direction. Fluid bearing. 5. Both ends of the shaft are substantially symmetrical with respect to the center of the shaft, a rotating body is attached to one end of the shaft, and the other end is used for position control in the thrust direction. The fluid bearing according to claim 4, wherein 6. When the shaft rotates in the first direction, a fluid film is formed by the first groove and the second groove, and the third groove is formed at an end of the shaft. The fluid bearing according to claim 4, which serves to supply a fluid. 7. When the shaft rotates in the second direction, a fluid film is formed by the first groove and the third groove, and the second groove is formed at an end of the shaft. The fluid bearing according to claim 4, which serves to supply a fluid.